The Women's Phantom 0 Degree Sleeping Bag by Mountain Hardwear. A favorite among the Mountain Hardwear alpine climbing team, the Phantom 0 is our lightest four-season bag. This snug mummy cut bag is insulated with 800-fill down, built from Superlight 15 denier fabric and tuck-stitched for durability. The Phantom 0 uses every trick in the book to keep you warm while being as light as possible.

• Determine the correct pack size by measuring from the top of your hip shelf to the C7 vertebrae, which is the protruding bump at the base of the neck.

• If you think you are between pack sizes, consider how and when you will be using the pack. For example, if you will be using the pack primarily in the winter, when more and bulkier clothing is required, you may opt to size up.

• You can find Torso Range and other size information in the description FEATURES or SPECIFICATIONS for each Mountain Hardwear pack. You can also refer to the size guide below to compare the current season packs by category.